Motion prediction for wireless power transfer

ABSTRACT

A signal generator generates an electrical signal that is sent to an amplifier, which increases the power of the signal using power from a power source. The amplified signal is fed to a sender transducer to generate ultrasonic waves that can be focused and sent to a receiver. The receiver transducer converts the ultrasonic waves back into electrical energy and stores it in an energy storage device, such as a battery, or uses the electrical energy to power a device. In this way, a device can be remotely charged or powered without having to be tethered to an electrical outlet.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit as a continuation-in-part of U.S.patent application Ser. No. 14/635,861, filed on Mar. 2, 2015, whichclaims the benefit of U.S. patent application Ser. No. 13/477,551, filedon May 22, 2012, which claims the benefit of U.S. Provisional PatentApplication No. 61/490,988, filed May 27, 2011, all of which are hereinincorporated herein by reference in their entirety. This application isalso related to U.S. patent application Ser. No. 13/477,542, entitled,“Sender Communications for Wireless Power Transfer”; U.S. patentapplication Ser. No. 13/477,551, entitled “Receiver Communications forWireless Power Transfer”; U.S. patent application Ser. No. 13/477,555,entitled “Sender Transducer for Wireless Power Transfer”; U.S. patentapplication Ser. No. 13/477,557, entitled, “Receiver Transducer forWireless Power Transfer”; U.S. patent application Ser. No. 13/477,565,entitled, “Sender Controller for Wireless Power Transfer”; and U.S.patent application Ser. No. 13/477,574, entitled, “Receiver Controllerfor Wireless Power Transfer”; all of which were filed on May 22, 2012,and each and every one of which is incorporated herein in its entirety.

BACKGROUND

Devices that require energy to operate can be plugged into a powersource using a wire. This can restrict the movement of the device andlimit its operation to within a certain maximum distance from the powersource. Even most battery-powered devices must periodically be tetheredto a power source using a cord, which can be inconvenient andrestrictive.

BRIEF SUMMARY

According to an embodiment of the disclosed subject matter, a systemcomprising at least one first transducer adapted and configured toconvert electrical energy to ultrasonic energy in the form of ultrasonicwaves. The first transducer is in communication with a first controller,and the first controller is in communication with a first communicationdevice.

In another embodiment of the disclosed subject matter, a systemcomprises at least one second transducer adapted and configured toconvert ultrasonic energy in the form of ultrasonic waves to electricalenergy. The second transducer is in communication with a secondcontroller, and the second controller is in communication with a secondcommunication device.

Additional features, advantages, and embodiments of the disclosedsubject matter may be set forth or apparent from consideration of thefollowing detailed description, drawings, and claims. Moreover, it is tobe understood that both the foregoing summary and the following detaileddescription are exemplary and are intended to provide furtherexplanation without limiting the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosed subject matter, are incorporated in andconstitute a part of this specification. The drawings also illustrateembodiments of the disclosed subject matter and together with thedetailed description serve to explain the principles of embodiments ofthe disclosed subject matter. No attempt is made to show structuraldetails in more detail than may be necessary for a fundamentalunderstanding of the disclosed subject matter and various ways in whichit may be practiced.

FIG. 1 shows a system in accordance with an embodiment of the invention.

FIG. 2 shows a system in accordance with an embodiment of the invention.

FIG. 3 shows a system in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

Embodiments of the disclosed subject matter can convert electricalenergy into acoustic energy, which can be beamed to a device where it isconverted back into electrical energy. The converted electrical energycan be used to power the device and to charge one or more energy storagecomponents of the device, such as a battery, a capacitor, etc. This canobviate the need for constant or periodic tethering to a power sourceusing a cord. Embodiments can transfer energy to several devices atonce, in rotation or in any suitable sequence, with dwell times of anysuitable duration.

FIG. 1 shows a system in accordance with the disclosed subject matter.Transmitter 101 can receive electrical energy from power source 102(such as an electrical outlet or a battery) as input. Signal generator103 can generate a signal that can be amplified by amplifier 104. Thiscan be done under the control of controller 105. The amplified signalcan be sent to sending transducer 106, and the ultrasonic energy in theform of ultrasound waves 107 can be transmitted through a medium such asthe air. Receiver 108 can includes receiving transducer 109, whichreceives ultrasonic energy in the form of ultrasonic waves and convertsit to electrical energy, which can be used to charge energy storagedevice 110 or power processor 111. Examples of energy storage device 110can include a battery, a capacitor, an induction circuit, etc. Examplesof device 105 can include a smartphone (such as an Android mobiledevice, an iPhone, a mobile device having a Microsoft operating system),a portable computer (such as an Apple laptop, a laptop having aMicrosoft operating system, etc.), an electronic content reader, (suchas the Amazon Kindle, the Apple iPad, etc.) and so on. Controller 111can control the receiving transducer 109 and/or energy storage device110.

Controller 105 can be coupled to antenna 112 and controller 111 can becoupled to antenna 113. As described below, the transmitter controller105 and receiver controller 111 can communicate through antennas 112 and113.

Sending transducer 106 can comprise a plurality of transducers arrangedin an array that can produce a focused beam of ultrasonic energy.Sending transducer 106 may include at least one Capacitive Micromachined Ultrasonic Transducer (CMUT), a Capacitive UltrasonicTransducer (CUT), an electrostatic transducer or any other transducersuitable for converting electrical energy into acoustic energy. Togenerate focused ultrasonic energy via a phased array, sendingtransducer 106 can include a timed delay transducer or a parametricarray transducer, or a bowl-shaped transducer array. Transmitter 101 canoperate for example between about 20 to about 120 kHz for transmissionof ultrasonic energy through air, and up to about 155 dB, for example.For ultrasonic transmission through other medium, transmitter 101 canoperate at frequencies greater than or equal to 1 MHz, for example.Sending transducer 106 may have a high electromechanical conversion, forexample an efficiency of about 40%, corresponding to about a 3 dB loss.

Transmitter controller 105 can cause the sending transducer 106 to emitultrasonic waves based on the proximity of the sending transducer 106(or transmitter 101 in general) to receiving transducer 109. Receivingtransducer 109 can convert ultrasonic energy received from sendingtransducer 106 to electrical energy. As used herein, proximity can bethe actual or effective distance between the sending transducer 106 orthe like and receiving transducer 109 or the like. Effective distancecan be based on the efficiency of energy transmission between sendingtransducer 106 and receiving transducer 109 based on various factorsthat can include, without limitation, their relative locations; thecharacteristics of the conductive medium (e.g., the air, tissue, etc.)between transmitter and receiver; the relative orientation of thetransmitter and receiver; obstructions that may exist between thetransmitter and receiver; relative movement between transmitter andreceiver; etc. In some cases, a first transmitter/receiver pair may havea higher proximity than a second transmitter/receiver pair, even thoughthe first pair is separated by a greater absolute distance than thesecond pair.

Transmitter controller 105 may cause a beam of ultrasonic energy to bedirected toward receiver transducer 109. Further, transmitter controller105 can cause sending transducer 105 to emit ultrasonic waves having atleast one frequency and at least one amplitude. Transmitter controller105 can cause the sending transducer 106 to change the frequency, phaseand/or amplitude of at least some of the ultrasonic waves based on theproximity and/or location of sending transducer 106 to receivingtransducer 109. Additionally, transmitter controller 105 can causesending transducer 105 to change the phase and/or amplitude of at leastsome of the ultrasonic waves based on the frequency of the ultrasonicenergy emitted by sending transducer or based on information regardingthe receipt of ultrasonic energy as determined by receiving controller111.

Sending controller 105 and receiving controller 111 can communicatethrough antennas 112 and 113. In this way, receiving controller canessentially control the character and amplitude of the energy generatedby sending transducer 106 by sending commands to sending controller 105.Also, sending controller 105 can control the characteristics of sendingtransducer 106 based upon data and/or commands received from receivingcontroller 111. Likewise, sending controller can control thecharacteristics of the energy sent by sending transducer 106independently of input from receiving controller 111.

Transmitter controller 105 can include a transmitter communicationsdevice (not shown) that can send an interrogation signal to detectreceiving transducer 109. The transmitter communications device can senda control signal to a receiver communications device (not shown) coupledto receiver controller 111. Receiver controller 111 can control receivertransducer 109. The control signal may include the frequency and/oramplitude of the ultrasonic energy emitted by sending transducer 106.The control signal can be used to determine the proximity and/ororientation of sending transducer 106 to receiving transducer 109.Additionally, the control signal may include an instruction to beexecuted by receiving controller 109 and may also include informationabout the impedance of sending transducer 106.

The sender communication device can receive a control signal from thereceiver communication device, which can be in communication withreceiver controller 111. The control signal may include a desired powerlevel, the frequency, phase, and/or amplitude of ultrasonic energyreceived from the sender transducer 106. Additionally, the controlsignal may include the impedance of the receiving transducer 109, arequest for power, and/or an instruction to be executed by thetransmitter controller 105. The control signal may be used to determinethe proximity of the sender transducer to the receiver transducer and/orthe relative orientation of the sender transducer to the receivertransducer. Further, the control signal may also indicate a powerstatus. Such a power status can indicate, for example, the amount ofpower available to the receiver 108, e.g., percent remaining, percentexpended, amount of joules or equivalent left in the receiver energystorage device 110. The control signal may be transmitted by modulatingat least some of the ultrasonic waves and/or may be transmittedout-of-band, e.g., using a separate radio frequency transmitter, or bysending a signal through a cellular telephone network or via a Wi-Finetwork, or using optical or infrared transmission. For example, thesignal may be transmitted by text, instant message, email, etc.

Transmitter 101 can further include a signal generator 103, variouslyknown as a function generator, pitch generator, arbitrary waveformgenerator, or digital pattern generator, which can generate one or morewaveforms of ultrasonic waves. A controller 105 can itself include anoscillator, an amplifier, a processor, memory, etc., (not shown.) Theprocessor of the controller can also execute instructions stored inmemory to produce specific waveforms using the signal generator 103. Thewaveforms produced by the signal generator 103 can be amplified by theamplifier 104. The controller 105 can regulate how and when thetransducer 106 can be activated.

The electrical power source 102 for transmitter 101 may be an AC or DCpower source, or may use a pulse superimposed on a DC bias, or anycombination of DC bias and time varying source. Where an AC power sourceis used, transmitter 101 may include a power processor 114 that iselectrically connected with the signal generator 103. The powerprocessor 114 can receive AC power from the power source 102 to generateDC power.

Transmitted ultrasound beams 107 can undergo constructive interferenceand generate a narrow main lobe and low-level side lobes to help focusand/or direct the ultrasonic energy. The ultrasonic energy generated bytransmitter 101 may also be focused using techniques such as geometricfocusing, time reversal methods, beam forming via phase lags, or throughthe use of an electronically controlled array.

The transmitter 101 may scan an area for receivers, may sense locationof a receiver within a room, may track a receiver, and may steer anultrasonic beam toward the receiver. Transmitter 101 may optionally notemit ultrasonic energy unless a receiver 108 is determined to be withina given range, or when a receiver 108 meets some other suitablecriteria, such as being fully charged or having an identifier that isvalid to the transmitter 101.

Transmitter 101 may be mechanically and/or electronically orientedtowards a receiver 108. For example, in some embodiments, thetransmitter can be tilted in the XY-direction using a motor, or may bein a pre-fixed position, and the beam can be steered electronically inthe Z-direction. The transmitter 101 may transmit ultrasonic energy tothe receiver 108 via line of sight transmission or by spreading theultrasound pulse equally in all directions. For line of sighttransmission, the transmitter 101 and receiver 108 may be physicallyoriented toward each other: the transmitter 101 can physically orelectronically (or both) be aimed at the receiver 108 or the receiver108 can be so aimed at the transmitter 101. The transmitter 101 maytransmit signals, such as an ultrasonic, radio, optical, infrared, orother such signal, to be sensed by the receiver 108 for the purpose ofdetecting orientation, location, communication, or other purposes, orvice versa. One or both of the transmitter 101 and receiver 108 caninclude a signal receiver such as antennas 112 and 113, respectively,that can receive signals from the receiver 108 or transmitter 101,respectively. Likewise, signals may be transmitted from transmitter 101to receiver 108 using the ultrasonic waves themselves.

The transmitter 101 can be thermo regulated by managing the duty cyclesof the signal generator and other components. Thermoregulation can alsobe achieved by attaching heat sinks to the transmitting transducer 106,using fans, and/or running a coolant through the transmitter, and otherthermoregulation methods, such as peltier and other thermoelectriccoolers.

Receiver 108 can include a receiver transducer 109 that can convertultrasonic energy in the form of ultrasonic waves to electrical energy.Receiver transducer 109 may include one or more transducers arranged inan array that can receive unfocused or a focused beam of ultrasonicenergy. Receiver transducer 108 may include at least one CapacitiveMicromachined Ultrasonic Transducer (CMUT), a Capacitive UltrasonicTransducer (CUT), or an electrostatic transducer, or apiezoelectric-type transducer described below, a combination thereof orany other type or types of transducer that can convert ultrasound intoelectrical energy. For receiving focused ultrasonic energy via a phasedarray, receiver transducer 109 may include a timed delay transducer or aparametric transducer. Receiver 108 can operate for example betweenabout 20 to about 120 kHz for receipt of ultrasonic energy through air,and up to any suitable DB level, such as about 155 dB, for example. Forreceiving ultrasonic energy through other medium, receiver 108 canoperate at frequencies greater than or equal to 1 MHz, for example.Receiver transducer 109 can have a high electromechanical conversionefficiency, for example of about 40%, corresponding to about a 3 dBloss.

Receiver transducer 109 may supply electrical energy to an energystorage device 110 and/or a processor 115. Examples of an energy storagedevice 110 can include, but are not limited to, a battery, a capacitivestorage device, an electrostatic storage device, etc. Examples of aprocessor can include, but not limited to, a processor or chipset for asmartphone (such as an Android mobile device, an iPhone, a mobile devicehaving a Microsoft operating system), a portable computer (such as anApple laptop, a laptop having a Microsoft operating system, etc.), anelectronic content reader, (such as the Amazon Kindle, the Apple iPad,etc.), a field-programmable gate array (FPGA), a graphic processing unit(GPU) using general-purpose computing on graphics processing units(GPGPU) and so on.

In accordance with various embodiments, receiver 108 can include areceiver transducer 109 that can be one or more of a piezoelectricallyactuated flexural mode transducer, a flextensional transducer, aflexural mode piezoelectric transducer, and/or a Bimorph, Unimorph, orTrimorph-type piezoelectric transducer (“PZT”) such as flexing typepiezoelectric element of the kind manufactured by Morgan ElectroCeramics. These can be attached to a metal membrane, or membrane of anyother suitable material, and the structure can resonate in a flexingmode rather than in a brick mode. In embodiments, the structure can beclamped around the rim by an attachment to the transducer housing. ThePZT slab can be electrically matched to the rectifier electronics. Thiscan be a high Q resonator (it can resonate at a single frequency) thatcan be held by very low impedance material.

Receiver 108 can further include a receiver controller 111 incommunication with the receiver transducer 109. Receiver controller 109can cause the receiver transducer 109 to receive ultrasonic waves basedon the proximity of the receiver transducer 109 to a sender transducer106. Receiver transducer 109 can convert ultrasonic energy received froma sender transducer 106 to electrical energy. Proximity can be theactual or effective distance between the receiver transducer 109 andsender transducer 106. Effective distance can be based on the efficiencyof energy transmission between receiver transducer 109 and sendertransducer 106 based on various factors that can include, withoutlimitation, their relative locations; the characteristics of theconductive medium (e.g., the air, tissue, etc.) between transmitter andreceiver; the relative orientation of the transmitter and receiver;obstructions that may exist between the transmitter and receiver;relative movement between transmitter and receiver; etc. In some cases,a first transmitter/receiver pair may have a higher proximity than asecond transmitter/receiver pair, even though the first pair isseparated by a greater distance than the second pair.

Receiver controller 109 may cause a beam of ultrasonic energy to bereceived from sender transducer 106. Further, receiver controller 109can cause the sender transducer 106 to receive ultrasonic waves havingat least one frequency and at least one amplitude.

Receiver 108 can further include a communication device (not shown) thatcan send an interrogation signal through antenna 113 to detecttransmitter 101 and help to determine characteristics of transmitter101, including sending transducer 106. The receiver communication devicecan send a control signal to a sender communication device, which can bein communication with sender controller 105. Sender controller 105 cancontrol sender transducer 106. The control signal may include thefrequency, phase and/or amplitude of the ultrasonic waves received byreceiver transducer 109. The control signal may be used to determine theproximity and/or relative orientation of receiver transducer 109 tosender transducer 106. Additionally, the control signal may include,without limitation, an instruction to be executed by sender controller105; the impedance of receiver transducer 109; a desired power level; adesired frequency, a desired phase, etc.

The receiver communications device may receive a control signal from asender communications device that can be in communication with sendercontroller 105. The control signal may include the frequency, phase,and/or amplitude of ultrasonic energy emitted by sender transducer 106.Additionally, the control signal may include an instruction to beexecuted by receiver controller 111 and may also include aninterrogation signal to detect a power status from receiver transducer109. The control signal may be used to determine the proximity and/orrelative orientation of receiver transducer 109 to sender transducer106.

A communications device can send a signal by modulating the ultrasonicwaves generated by the transducer for in-band communications. Thecommunication device can also be used to modulate an out-of-band signal,such as a radio signal, optical signal, or infrared signal, forcommunication to another communication device. The radio signal can begenerated by a separate radio transmitter that may use an antenna.

The system may include communication between receiver and transmitterto, for example, adjust frequency to optimize performance in terms ofelectro acoustical conversion, modulate ultrasonic power output to matchpower demand at a device coupled to the receiver, etc. For example, ifit is determined that the ultrasound waves received by the receiver 108are too weak, a signal can be sent through the communications devices tothe transmitter 101 to increase output power. Sender controller 105 canthen cause sending transducer 106 to increase the power of theultrasonic waves being generated. In the same way, the frequency,duration, phase, and directional characteristics (such as the degree offocus) of the ultrasonic waves may be adjusted accordingly.

Thus, in accordance with embodiments of the disclosed subject matter,the transmitter 101 and receiver 108 can communicate to coordinate thetransmission and receipt of ultrasonic energy. Communications betweenthe transmitter 101 and receiver 108 can occur in-band (e.g., using theultrasonic waves that are used to convey power from the transmitter tothe receiver to also carry communications signals) and/or out-of-band(e.g., using separate ultrasonic waves from those used to carry poweror, for example, radio waves based on a transmitter or transceiver atthe transmitter and receiver.) In an embodiment, a range detectionsystem (not shown) can be included at the transmitter 101, at thereceiver 108 or both. The range detection system at the transmitter canuse echolocation based on the ultrasound waves sent to the receiver, theBluetooth wireless communications protocol or any other wirelesscommunications technology suitable for determining the range between adevice and one or more other devices. For example, the strength of aBluetooth or Wi-Fi signal can be used to estimate actual or effectiverange between devices. For example, the weaker the signal, the moreactual or effective distance can be determined to exist between the twodevices. Likewise, the failure of a device to establish a communicationslink with another device (e.g., using a Bluetooth or Wi-Fi (e.g.,802.11) signal with another device can establish that the other deviceis beyond a certain distance or range of distances from a first device.Also, a fraction of the waves can reflect back to the transmitter fromthe receiver. The delay between transmission and receipt of the echo canhelp the transmitter to determine the distance to the receiver. Thereceiver can likewise have a similar echolocation system that uses soundwaves to assess the distance between the receiver and the transmitter.

In an embodiment of the presently disclosed subject matter, impedance ofthe first 106 and second 109 transducers may be the same and/or may besynchronized. In this regard, for example, both transducers 106 and 109may operate at the same frequency range and intensity range, and havethe same sensitivity factor and beam width.

Communications between transmitter 101 and receiver 108 can also be usedto exchange impedance information to help match the impedance of thesystem. Impedance information can include any information that isrelevant to determining and/or matching the impedance of the transmitterand/or receiver, which can be useful in optimizing the efficiency ofenergy transfer. For example, a receiver 108 can send impedanceinformation via a communication signal (e.g., a “control signal”) thatincludes a frequency or a range of frequencies that the receiver 108 isadapted to receive. The frequency or range of frequencies may be theoptimal frequencies for reception. Impedance information can alsoinclude amplitude data from the receiver 108, e.g., the optimalamplitude or amplitudes at which a receiver 108 can receive ultrasoundwaves. In an embodiment, an amplitude is associated with a frequency toidentify to the transmitter 101 the optimal amplitude for receivingultrasound at the receiver 108 at the specified frequency. In anembodiment, impedance information can include a set of frequencies andassociated amplitudes at which the receiver 108 optimally can receivethe ultrasound waves and/or at which the transmitter 101 can optimallytransmit the ultrasound. Impedance information can also includeinformation about the sensitivity of the transmitter 101 and/or receiver108, beam width, intensity, etc. The sensitivity may be tuned in someembodiments by changing the bias voltage, at least for embodiments usingCMUT technology.

Communications can also include signals for determining locationinformation for the transmitter 101 and/or the receiver 108. Inaccordance with embodiments of the disclosed subject matter, locationinformation for receivers 108 can be associated with receiveridentifiers (e.g., Electronic Identification Numbers, phone numbers,Internet Protocol, Ethernet or other network addresses, deviceidentifiers, etc.) This can be used to establish a profile of thedevices at or near a given location at one time or over one or more timeranges. This information can be provided to third parties. For example,embodiments of the system may determine a set of device identifiers thatare proximate to a given location and to each other. The fact that theyare proximate; the location at which they are proximate; informationabout each device (e.g., a device's position relative to one or otherdevice, a device's absolute location, power information about a device,etc.) can be shared with a third party, such as an third partyapplication that would find such information useful. Further, similarsuch information can be imported into embodiments of the presentinvention from third party sources and applications.

Embodiments of communications protocols between transmitter 101 andreceivers 108 can be used to dynamically tune the beam characteristicsand/or device characteristics to enable and/or to optimize thetransmission of power from transmitter 101 to receiver 108. For example,at a given distance, it may be optimal to operate at a given frequencyand intensity. A transmitter 101 may server several different devicesby, for example, steering and tuning the beam for each receiver device108, e.g., in a round-robin or random fashion. Thus, the beam for adevice A may be at 40 kHz and 145 dB, device B may be at 60 kHz and 130dB and device C at 75 kHz and 150 dB. The transmitter can tune itself totransmit an optimally shaped beam to each of these dynamically, changingbeam characteristics as the transmitter shifts from one device toanother. Further, dwell time on each receiver device 108 can bemodulated to achieve particular power transfer objectives.

In an embodiment, a transmitter 101 can receive a signal (one or morecontrol signals) from a receiver 108 indicating one or more of thereceiver's distance, orientation, optimal frequencies, amplitudes,sensitivity, beam width, etc. For example, optimal frequency when areceiver is less than 1 foot away from a transmitter may be 110 kHz witha 1.7 dB/ft attenuation rate, and optimal frequency when a receiver isfarther than 1 foot away from a transmitter may be 50 kHz with a 0.4dB/foot attenuation rate. The receiver can detect the distance andprovide a signal to the transmitter to change its frequency accordingly.In response, the transmitter can tune itself to transmit the best beampossible to transfer the most power in the most reliable fashion to thereceiver. These parameters can be dynamically adjusted during thetransmission of ultrasonic energy from the transmitter to the receiver,e.g., to account for changes in the relative positions of thetransmitter and receiver, changes in the transmission medium, etc.

Likewise, a receiver 108 may configure itself in response to signalsreceived from a transmitter 101. For example, a receiver 108 may tune toa given frequency and adjust its sensitivity to most efficiently receiveand convert ultrasound waves from the transmitter 101 to electricalenergy.

Dwell time of a transmitter 101 on a receiver 108 can also be adjustedto optimize the energy delivered by a transmitter to several receiversaround the same time. For example, the transmitter 101 may receive powerrequirements information from each of five receivers. It may dwell onthe neediest receiver for a longer time interval than a less needyreceiver as it services (e.g., sends ultrasound waves to) each receiver,e.g., in round-robin fashion.

Embodiments of the present invention include a system that can include asender transducer coupled to the amplifier. The sender transducer can bea capacitive micromachined ultrasound transducer, another type ofcapacitive ultrasound transducer, an electrostatic ultrasoundtransducer, a piezoelectric type ultrasound transducer, etc. Acapacitive transducer includes any transducer that converts anycapacitively-stored energy into ultrasonic energy. An electrostatictransducer is one that uses any electrostatically-stored energy intoultrasound energy. A piezoelectric-type transducer is one that generatesultrasonic energy based on subjecting dielectric crystals toelectricity, resulting in the crystals experiencing mechanical stress.

The transducer can be configured as an array of transducers and/orapertures. This can be used to produce a beam of ultrasonic energy. Thetransducer can be controlled by the sender controller to produce one ormore ultrasonic beams and can produce each such beam or combination ofbeams with a given shape, direction, focal length, width, height, andshape, and any other focal property of the beam. The transducer caninclude one or more steering components, including one or moreelectronic steering components, e.g., one or more configurations orpatterns or array elements and/or apertures. One or more of theapertures can be convex to help control beam properties such as focallength. A transducer can have a mechanical steering component that worksalone or in combination with one or more electronic steering componentsto control focal properties of one or more ultrasonic beams. Atransducer may also have subsections that are prepositioned in differentorientations.

In accordance with embodiments of the present invention, a system caninclude a sender that has a first value of a configuration parameter. Aconfiguration parameter can be used to describe an actual or potentialstate or condition of a sender or a receiver and can include, forexample, an amplitude, a frequency, a steering parameter, aninstruction, a power status, a transmitter characteristic and a receivercharacteristic. A sender characteristic can describe an actual orpotential condition of the sender or receiver. For example, a sendercharacteristic can relate to the power state of the sending transducerand have the values ON (emitting ultrasound to be converted intoelectrical energy by a receiver) or OFF. Another power configurationparameter can relate to the power level of the emitted ultrasonic energyin various units, such as watts per square inch, decibels, etc.

A characteristic can describe an actual or potential condition of thesender or receiver that can be fixed. For example, a characteristic canbe a telephone number, Electronic Serial Number (ESN), Mobile EquipmentIdentifier (MEID), IP address, MAC address, etc., or a mobile orstationary device that can be a sender or receiver. A characteristic canbe a fixed impedance or other electronic property (e.g., transducertype, software/firmware version, etc.) of a device.

In accordance with embodiments of the present invention, a device has afirst configuration parameter. Based on input received through thesender communications device, the sender can change its configurationparameter value to a second configuration parameter value and therebychange its state and/or behavior. Mechanisms for changing the senderconfiguration parameter can include receiving a new configurationparameter value through the communications device. The new configurationparameter value can originate from a receiver to which the sender is orintends to transmit ultrasonic energy. For example, a sender can betransmitting ultrasonic energy at a first power level and a receiver cansend a message to the sender requesting that the energy be transmittedat a second power level. For example, a receiver can send a requestasking that the power of transmitted ultrasound be boosted from 120 dBto 140 dB. The sender can then change its power level configurationparameter from 120 dB to 140 dB.

Another mechanism is to change a first configuration parameter based oninput received through the communications device, even when that inputdoes not specify a new (second) value for the configuration parameter.For example, input can be received at the sender communications devicefrom a receiver that includes a request to increase the power of thetransmitted ultrasonic energy. In response, the sender can change thevalue of the power configuration parameter from the first value to asecond value, e.g., from 120 dB to 140 dB. Likewise, one or moreconfiguration parameters can be changed based on a combinations ofinputs from one or more receivers or third parties. For example, a beamshape can be changed based upon a receiver characteristic, such as thetype of receiver transducer at the receiver.

A configuration parameter can be or include one or more steeringparameters. Examples of steering parameters include a steering angle,such as the angle at which a mechanical tilt device has disposed or candisposed one or more elements of a transducer; a dispersion angle, suchas the angle at which a threshold power occurs in an ultrasonic beam(e.g., the beam width expressed as an angle); a focal length, such as adistance in centimeters at which an ultrasonic beam becomes mostfocused; a transmitter location, such as the angle and distance of areceiver from a transmitter, or the distance of a transmitter from areceiver, or the absolute position (e.g., from a given reference point)of a sender or receiver; and a relative orientation of a sender andreceiver, such as the difference in the relative orientation of a sendertransducer and a receiver transducer, expressed in the degrees fromparallel. For example, when one transducer is parallel to another, theycan be said to have a zero degree offset. When one is perpendicular inorientation to another, they can have a ninety degree offset, etc.

Another mechanism is to change a first steering parameter in order toadjust and/or improve the efficiency of the transmission of ultrasonicenergy to a receiver. The steering parameter can be changed based oninput received through the communications device, even when that inputdoes not specify a new (second) value for the steering parameter. Forexample, input can be received at the sender communications device froma receiver that includes an amount of the transmitted ultrasonic energybeing received, e.g., 120 dB. In response, the sender can change thevalue of the steering parameter, e.g., relative orientation, from thefirst value to a second value, e.g., from a ninety degree offset to azero degree offset. As a result of changing/adjusting the steeringparameter, the efficiency of the transmission of ultrasonic energy tothe receiver may improve, and the amount of the transmitted ultrasonicenergy being received may increase, e.g., from 120 dB to 140 dB. Forexample, the amount of power at the receiver can be monitored by thereceiver and used as a basis for generating an input to be sent to thesender to adjust one or more of its configuration parameters. This canchange the way in which ultrasonic energy is transmitted by the senderto the receiver, e.g., by changing the tilt of a mechanical steeringmechanism for the sender transducer, by changing the power level of thetransmitted ultrasonic energy, by changing the electronic steering andbeam shaping of the ultrasonic energy at the sender, etc. In this way,the receiver can provide real-time or near-real-time feedback to thesender so that the sender can tune the way in which it sends ultrasonicenergy to the receiver to improve the rate at which energy istransferred (e.g., power), the continuity of energy transfer, theduration of energy transfer, etc.

Beam steering and focusing can be achieved by causing the controller tomodulate (control) the phase of the electrical signal sent to thesending transducer or to various elements of the sending transducer. Forwide-angle steering, elements of size λ/2 can be used, e.g., having asize of around 4 mm. Some semiconductor companies (Supertex, Maxim,Clare, etc.) manufacture high voltage switch chips that can allow a fewhigh-power oscillator circuits to take the place of thousands oftransmitters. An example of a useful design can have four oscillatorswith phases of 0, π/2, π and 3π/2. Switches can be arranged so that eachtransmit element can be connected to any of the four phases. The pitchof the switch-matrix can then be smaller than the pitch of thetransducer array, which can facilitate interconnection. A small amountof memory can store the entire set of switch arrangements needed for anarbitrary number of steering and focusing positions. A simplemicrocontroller (e.g., an ARM microcontroller) can manage thesteering/focusing computation.

Beam steering and focusing can be made more manageable in various ways.An electronic steering mechanism can be combined with a mechanical tiltmechanism in a direction orthogonal to that of the electronic steeringmechanism to steer and focus the beam. For example, the transmitter canbe relatively fixed in azimuth (horizontal dimension) but mechanicallysteerable in elevation (vertical dimension). Tracking vertically can beachieved by a mechanical tilt, driven by the signaling from thereceiver, or from a transmitter, either directly or through thereceiver, or with input from both and/or a third party, such as apower-tracking server. Electronic steering and focusing can be used forthe azimuthal (horizontal) beam.

Some embodiments can tilt in both azimuth and elevation. In such cases,a two dimensional array with certain elements (e.g., a 15×15 array of 2λelements with regular or variable separation between the elements) canperform focusing and steering. In some embodiments, the element size cangrow from λ/2 to 2λ or larger. In some embodiments, the electronicallysteered array can be embedded in a mechanically focused transducer. Asmaller matrix array can be positioned at the center of curvedtransducer. The curvature can create a focus in a given direction and ata certain average depth, e.g., one meter. The electronically focusingportion in the center can further adjust the focusing characteristics ofthe beam.

In some embodiments, the output can be split asymmetrically betweenazimuth and elevation, allowing for sophisticated beam control. Invarious embodiments, the aperture can be divided into severalsub-apertures. Some or all of the sub-apertures can have differentsteering capabilities, enabling such an arrangement to produce aplurality of foci, which may be adjacent to each other. FIG. 2 shows adivided aperture apparatus in accordance with embodiments of the presentinvention. Source aperture 201 of can be divided into separatesub-apertures 202, 203 and 204. Each sub-aperture 202, 203 and 204 hasits own target focus 205, 206 and 207, respectively. The phase of eachof the three sources shown in FIG. 2 can be altered to change the focallength of the elevation aperture. The beam steering can be mechanical,electronic, or a combination of the two. This arrangement can also befocused by changing the phase between the sources. The efficiency of thetransmitter can be maintained for targets over a range of depths aroundthe mechanical foci established by the curvature of the sources. Thepower level supplied to a target may be kept constant.

FIG. 3 shows another focusing apparatus that uses azimuth aperturedivision to allow for an extended focus range over the target. Sourcetargets 301, 302, 303 and 304 have respective target foci 305, 306, 307and 308. Steering and focusing can be accomplished electronically,mechanically, or a combination thereof. In the embodiment shown in FIG.3, the element size can be made small enough to avoid the need foraperture curvature and/or mechanical tilt. Dividing the array intosegments can increase the size of the focal spots and allow them to bejuxtaposed. The foci can move around on the surface of the receiver,e.g., to optimize the overall power transfer.

A mobile device application (e.g., an iPhone or Android application) maybe associated with an embodiment of the present system to aid the user.The associated mobile application may locate an ultrasonic power system,in accordance with an embodiment of the disclosed subject matter, nearor within range of the user's location. The mobile application maypinpoint the user's exact location and compare it to the strongest powersignal location in the room, and direct the user to that power location.The mobile application may communicate with corresponding applicationson other mobile devices, e.g., to share location information,transmitter and/or receiver information, data about the transmissivityof a given medium, etc.

In accordance with embodiments of the present invention, a given devicemay act as essentially as a relay between an initial transmitter and aterminal receiver device. Such a device (a “relay device” or an“intermediate device”) may receive power from a first device, convert atleast a part of the received power to electrical energy, re-convert itto acoustic energy and then beam that acoustic energy to the terminalreceiver device. This can be useful when the terminal device may be outof range of the initial transmitter device, especially when the initialtransmitter device stores a substantial amount of energy or is connectedto a larger source of energy, such as an electrical outlet or a largeexternal battery. This can also be used to arrange for a transfer energyfrom a device that has sufficient or an excess amount of stored energyto a device in need of energy, even when the latter may be out of rangeof the former without a relay or intermediate device.

The mobile application may also inform the user of how quickly itsmobile application device is being charged and how much more powerand/or time the device requires until it's fully charged. Additionally,the mobile application can indicate the user's “burn rate” based on theamount of data being used on the device at a given time based on avariety of factors, for example, how many programs/applications are openand can indicate that the device will need to charge again in a giventime period. The mobile application may tell the user when the device isusing power from the device battery or power from the wireless powersystem. For example, the mobile application may have a hard or softswitch to signal the transmitter when the device battery is less than20% full, thereby reducing the use of dirty energy and allowing thesystem to supply the most power to those who need it to the most.Additionally, the user may have the ability to turn off their ultrasonicreceptor and/or transmitter using the mobile application.

At least part of the receiver 108 may be in the shape of a protectivecase, cover, or backing for a device, such as a cell phone, that may beinside or outside the physical device. An energy storage device, such asa rechargeable battery, may be embedded within the receiver case. Thereceiver 108 may also be used in other devices such as a laptop, tablet,or digital reader, for example in a case or backing therefor. Thereceiver 108 may be embedded within the electronic housing or can be aphysical attachment. The receiver 108 can be any shape or size and canfunction as an isolated power receiver or be connected to a number ofdevices to power them simultaneously or otherwise.

In an embodiment of the disclosed subject matter, the receiver 108 canbe a medical device such as an implant, for example a pacemaker, or drugdelivery system. The implant can be powered, or the storage device canbe charged, using an ultrasonic transmitter 101. The characteristics ofthe transmitter 101 and/or receiver 108 can be tuned taking into accountthe power needs of the device, the conduction parameters of the tissuebetween the transmitter 101 and receiver 108, and the needs of thepatient. For ultrasonic power transmission through animal or planttissue, the receiver 108 can be embedded in a medical device and/ortissue to power or charge a chemical deliver or medical device such asan implanted device. For example, a transmitter 101 could be programmedto emit ultrasound waves at a given time to a receiver 108 locatedwithin a pacemaker device implanted in the body of a patient.

Certain embodiments of the present invention can be designed to delivera relatively uniform pressure to a rectangle such as a surface of, on orin a mobile device. For example, an embodiment can be designed todeliver acoustic energy to a mobile device such as a smartphone of size115×58 mm at a distance of one meter from the transmitter with atransmit frequency in the range of 40-60 kHz (i.e. the wavelength can be5.7 to 8.5 mm.)

The maximum power in some embodiments from transmitter to receiver canbe 316 W·m⁻², while the normalized amplitude or “gain” can becharacterized as the pressure created from 1 Pa at the surface of thetransmitter. A gain of less than one could mean that the energy transferis less than ideal. A gain above one could mean that the power densityat the transmitter should be reduced, e.g., for regulatory compliance,which may also be less than ideal. A design could create a gain of one,constant over the receiver area, and a gain less than one everywhereelse. The system can track the motion of the phone and limit power lossin the face of relative motion and/or position change of the transmitterin relation to the receiver and/or vice versa.

Phase change across the phone can be minimized, even in view of changesin the angle between the plane of the transmitter and receiver, whichcan be facilitated by using separate receiver patches on the phoneand/or with a multi-element transmitter, which can also raise theoverall efficiency through better control of the acoustic field.Steering and focusing can be achieved electronically by varying thephase of the transmitter wave across the elements. Different steeringangles and focus depths can have different values of phase at eachelement.

Various embodiments of the present invention can track the relativeposition and orientation of a transmitter and receiver, e.g., through aniOS or Android application and a wireless protocol such as Bluetooth or802.11, or through optical or infrared signals. Closed-loopcommunication between transmitter and receiver can permit the transmitbeam to track the mobile device to minimize the phase changes of thebeam across an element on or in the receiver.

When a receiver arrives within range of a transmitter, a two-waycommunication can be initiated. The receiver can signal its location andrequest transmission of acoustic power. As charging takes place, thephone can update the transmitter about its location, the amount of powerreceived and the distribution of acoustic energy at the receiver. Analert can be sent if the receiver is positioned in an orientation orlocation where the power transfer is inefficient. The transmitter mayalso be able be predict the motion of a receiver. For example, thetransmitter may store a location history for a particular receiver, suchas a phone. The location history may include the location andorientation of the receiver. The transmitter may use the locationhistory for the receiver and, optionally, a current location andorientation of the receiver to predict future locations and orientationsfor the receiver. This may allow the transmitter to direct wirelesspower, for example, through ultrasonic waves, to a location where thereceiver is expected to be next. This may result in more efficientdelivery of wireless power to a moving receiver, as a transmitter whichattempts to transmit wireless power to a current location of thereceiver may result in the wireless power, for example, in the form ofultrasonic or electromagnetic waves, trailing a moving receiver,arriving at a location as the receiver leaves that location. Atransmitter that is able to predict the next location and orientation ofthe receiver may be able to transmit wireless power to a location as thereceiver arrives at the location in a manner suitable for theorientation of the receiver as it arrives at the location, so thedelivery of wireless power to a location better coincides with thepresence of a moving receiver at that location and the orientation ofthe receiver when it arrives at that location. For example, thetransmitter may adjust the phase and focus of transmitted wireless powerbased on the orientation of the receiver.

Motion prediction for a receiver may be accomplished in any suitablemanner. For example, the past location of a receiver may be expressed asa set of (location,time) values, where the location may be an absolutelocation (e.g., latitude/longitude) or relative, such as a displacement(such as a (direction,distance) value pair) from its last location, andmay also indicate the orientation of the receiver. Likewise, the timemay be an absolute time (e.g., a Greenwich Mean Time) or a relativetime, such as an elapsed time since the last (location,time)measurement. The past (location,time) values can be used to calculate avelocity (speed and direction) and acceleration of the receiver. Thesecalculated values can be used to extrapolate from the last or recentknown positions of the receiver to generate one or more predicted(location, time) values for the receiver. A beam of energy from thetransmitter can be directed to be focused at the predicted locations,through beam steering, and in manners suitable for the predictedorientations, at the predicted times.

In another implementation, the (location,time) history of the receivercan be combined with other data to arrive at one or more predicted(location,time) values. For example, the location of walls and obstaclesin a room may be used to modify (location,time) predictions for thereceiver based on (location,time) history values. For example, thereceiver cannot pass through a solid wall and may not be able to bewithin certain spaces within a threshold value of boundaries of wallsand obstacles. Examples of obstacles can include tables, chairs,fixtures, and the like. Exceptions can be made for doors, whose knownlocations can be taken into account in generating predictive(location,time) values.

Behavioral history can also be used to generate predictive(location,time) values. Such behavioral data can be only for the presentreceiver or for more than one receiver. For example, a path history canbe generated that functions as a theoretical and/or empiricalprobability function for the path of a receiver in a given room.Theoretically, the implementation can assume that a receiver path thathas more than a threshold amount of trajectory (path) toward a knownlocation of a door will pass through the door. This can be used toinfluence the projected (location,time) values, including orientation,of a receiver that has moved more than the threshold amount of path inthe direction of a known door. Empirically, data can be gathered basedon numerous known receiver paths and common pathways can be established.For example, historical receiver path data may indicate that a commonpath taken by many receivers. For example, a common path may be from awork area towards the middle of a room, a deviation around a knownobstacle such as a coffee table, ending in an area proximate to a knownlocation of a coffee machine. An implementation can use the common pathby predicting (location,time) values based on (location,time) values fora give receiver that falls within a threshold distance of the commonpath for a threshold length of the path. For example, if a receiver hastraversed 65% of a common path without deviating more than two feet fromthe common path, the transmitter may determine a predicted set of(location,time) values for the receiver on or near the common path.These predicted path values can be refined based on velocity and/oracceleration data being sent from the receiver (e.g., from one or moresensors on the receiver), velocity and acceleration calculations basedon (location,time) values for the receiver, and the like. Thetransmitter may also account for the type of receiver and usage andmovement pattern of different receiver types. For example, mobiledevices such as smartphones may have different movement patterns thantablets or laptop computers due to their sizes and the manner in whichusers use and carry them.

The receiver may include various sensors, such as accelerometers, GPS orequivalent, which may be used to provide motion data to the transmitter.The receiver may include a receiver transducer, which may be used in animaging mode to evaluate the location of the receiver. The receiver mayalso send position and/or velocity data to the transmitter based onbeacon data processed by the receiver. Likewise, the receiver mayinclude radiators such as electromagnetic (e.g., infrared) transmittersor acoustic (e.g., ultrasound) beacons, or have acoustic orelectromagnetic wave reflectors that can passively return signals fromlocation signals sent from the transmitter, or from another device. Thetransmitter may adjust any suitable characteristic of the delivery ofwireless power to direct wireless power at a predicted future locationof a receiver. For example, the transmitter may adjust the steering,focus, phase, power density, frequency, amplitude, or any other suitablecharacteristic of ultrasonic waves. The transmitter may also be able todetermine and track the location of a receiver using a sendertransducer, which may be used in an imaging mode.

When transmitting wireless power to the predicted location of areceiver, the transmitter may account for the time of flight of thewireless power from the transmitter to the predicted location. Forexample, transmitted ultrasonic waves may take some time to travel froma transmitter to a predicted location of a receiver targeted by atransmitter. The transmitter may determine time of flight based on thedistance between the transmitter and the predicted location of thereceiver and on environmental conditions that may affect thetransmission, such as, for example, temperature, humidity, and airflow,which may affect the transmission of ultrasonic waves. For example,ultrasonic waves may cover a distance of 4 meters in 11 milliseconds. Ifa receiver is moving at a speed of 1.5 meters per second, the receivermay move 1.5 centimeters between the time ultrasonic waves are generatedand the time they reach the location targeted by the transmitter. 1.5centimeters may be 2 to 3 wavelengths of 50 kHz sound, as transmittedthrough the air, and may be the size of 6 ultrasonic elements on thereceiver. The transmitter may account for the 11 millisecond flighttime, and 1.5 centers of motion during that flight time, whendetermining the predicted location to be targeted with ultrasonic waves.For example, the transmitter may adjust a predicted location for areceiver by 1.5 centimeters, so that the receiver is more likely toarrive at the same location as the ultrasonic waves at the same time asthey ultrasonic waves, rather than having the ultrasonic waves trail thereceiver by 1.5 centimeters due to flight time.

The foregoing description, for purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive or tolimit embodiments of the disclosed subject matter to the precise formsdisclosed. Many modifications and variations are possible in view of theabove teachings. The embodiments were chosen and described in order toexplain the principles of embodiments of the disclosed subject matterand their practical applications, to thereby enable others skilled inthe art to utilize those embodiments as well as various embodiments withvarious modifications as may be suited to the particular usecontemplated.

The invention claimed is:
 1. A system, comprising: a sender comprising:a first signal generator; a first amplifier coupled to the first signalgenerator, said first amplifier configured to receive power from a powersource and to generate an electrical transmission signal adapted to beused to generate ultrasonic waves; a sender transducer coupled to thefirst amplifier, the sender transducer adapted and configured togenerate ultrasonic waves based on the electrical transmission signalreceived from the amplifier; a sender controller coupled to at least oneof the first signal generator, the first amplifier and the sendertransducer, the sender controller adapted and configured to adjust asteering parameter to direct the ultrasonic waves generated by thesender transducer to a predicted future location of a receiver; and asender communications device adapted to communicate with a receivercommunications device; and the receiver comprising: a receivertransducer adapted and configured to receive ultrasonic waves generatedby the sender transducer, to generate a receiver electrical signal basedon the received ultrasonic waves, and to connect to a receiverelectrical storage device adapted and configured to store electricalenergy based on the receiver electrical signal generated by the receivertransducer; a receiver communications device adapted and configured tosend input to the sender communications device; and a receivercontroller coupled to at least one of the receiver transducer and thereceiver electrical storage device.
 2. The system of claim 1, whereinthe receiver further comprises: a receiver electrical storage deviceadapted and configured to store electrical energy based on the receiverelectrical signal generated by the receiver transducer.
 3. A system,comprising: a signal generator; an amplifier coupled to the signalgenerator, said amplifier configured to receive power from a powersource and to generate an electrical transmission signal adapted to beused to generate ultrasonic waves; a sender transducer coupled to theamplifier, the sender transducer adapted and configured to generateultrasonic waves based on the electrical transmission signal receivedfrom the amplifier; a sender controller coupled to at least one of thesignal generator, the amplifier and the sender transducer, the sendercontroller adapted and configured to adjust a steering parameter todirect the ultrasonic waves generated by the sender transducer to apredicted future location of a receiver; and a sender communicationsdevice adapted to communicate with a receiver and receiver.
 4. Thesystem of claim 3, wherein the sender controller is further adapted toadjust at least one configuration parameter to orient the ultrasonicwaves generated by the sender transducer based on a predicted futureorientation of the sender.
 5. The system of claim 3, wherein the sendercommunications device is further adapted to receive input from thereceiver, the input comprising a control signal comprising an indicationof the motion of the receiver.
 6. The system of claim 5, wherein thesender controller is further adapted and configured to adjust thesteering parameter based on the control signal comprising the indicationof motion of the receiver.
 7. The system of claim 3, wherein thepredicted future location of the receiver is based on one or more of alocation history for the receiver, a type of the receiver, and a currentlocation of the receiver.
 8. The system of claim 5, wherein the controlsignal comprising the indication of the motion of the receiver comprisesdata from an accelerometer of the receiver.
 9. The system of claim 3,wherein the sender controller is further adapted and configured toadjust one or more of the phase, focus, power density, frequency, or anamplitude, based on the predicted future location of the receiver.
 10. Asystem comprising: a receiver transducer adapted and configured toreceive ultrasonic waves generated by a sender transducer and togenerate a receiver electrical signal based on the received ultrasonicwaves, the receiver transducer further adapted and configured to beconnected to a receiver electrical storage device adapted and configuredto store electrical energy based on the receiver electrical signalgenerated by the receiver transducer; a receiver communications deviceadapted and configured to send input to a sender communications device,the input comprising a control signal comprising an indication of one ormore of a motion of the receiver and an orientation of the receiver; anda receiver controller coupled to at least one of the receiver transducerand the receiver electrical storage device.
 11. The system of claim 10,wherein the control signal comprising an indication of the motion of thereceiver comprises data from an accelerometer of the receiver.
 12. Thesystem of claim 10, further comprising: a receiver electrical storagedevice adapted and configured to store electrical energy based on thereceiver electrical signal generated by the receiver transducer.
 13. Amethod comprising: emitting ultrasonic waves from an ultrasonictransducer of a sender, the ultrasonic waves directed at a receiver;determining a predicted future location of the receiver, wherein thepredicated future location of the receiver is based on one or more of alocation history of the receiver, a type of the receiver, and a currentlocation of the receiver; and steering the ultrasonic waves based on thepredicted future location of the receiver.
 14. The method of claim 13,further comprising: receiving a communication at the sender from thereceiver, the communication comprising a control signal comprising anindication of the motion of the receiver; and determining the predictedfuture location of the receiver based on the control signal comprisingthe indication of the motion of the receiver.
 15. The method of claim13, wherein steering the ultrasonic waves based on the predicted futurelocation of the receiver further comprises adjusting one or more of asteering parameter, phase, focus, power density, frequency, or anamplitude, based on the predicted future location of the receiver. 16.The method of claim 13, wherein determining a predicted future locationof the receiver further comprises determining a predicted futureorientation of the receiver; and further comprising: orienting theultrasonic waves based on the predicted future orientation of thereceiver.
 17. A method comprising: receiving ultrasonic waves from anultrasonic transducer of a sender at a receiver; determining a motion ofthe receiver; and sending a communication to the sender, thecommunication comprising a control signal comprising an indication oneor more of the motion and an orientation of the receiver.
 18. The methodof claim 17, wherein determining the motion of the receiver is based ondata from an accelerometer of the receiver.